DE-A 10 11 8630 and DE-A 10 15 9544 disclose LEDs having glass parts. U.S. Pat. No. 5,965,469 discloses a phosphate glass which is used as an adhesive.
DE-Az 10 2010 028 776.8 discloses metal phosphates as a matrix for conversion elements, wherein multiple phosphors can also be contained in one layer.